Generally, a hydraulic excavator, typical of construction machines, is largely constituted by an automotive vehicular lower structure, an upper revolving structure which is swingably mounted on the vehicular lower structure, and a working mechanism liftably mounted on a front portion of the upper revolving structure.
Normally, the upper revolving structure is largely constituted by a revolving frame serving as a support structure, a cab which is built on a left front portion of the revolving frame to define an operating room, a counterweight which is provided at the rear end of the revolving frame as a weight balance against the working mechanism, and a housing cover which is provided on the revolving frame on the front side of the counterweight. The housing cover is provided to accommodate onboard equipments which are mounted on the revolving frame, including an engine, hydraulic pump and heat exchanger (e.g., see Japanese Patent Laid-Open No. 2000-64348 and 2002-129592).
In the case of hydraulic excavators of the prior arts, normally a housing cover is fixed on a revolving frame by means of seat screw members which are fixed by welding or the like. At the time of fixing a housing cover on a revolving frame, bolts are threaded into seat screw members through bolt through holes which are provided in the housing cover.
In this regard, since the housing cover is a heavy structure, normally it becomes necessary to put the housing cover tentatively on top of the revolving frame, while bringing a bolt or bolts into alignment with a seat screw member or members prior to threading and tightening the bolts into the latter.
On such an occasion, normally anti-corrosive sealing material is provided at joint portions of the revolving frame and each seat screw member, for sealing the joint portions against corrosion which might develop at joint portions of the revolving frame and seat screw members when not coated with a paint to a sufficient degree.
However, when setting a bolt threaded into the housing cover in position to the seat screw member on the revolving frame, the housing cover is inadvertently put on top of the revolving frame in some cases, bringing the lower end of the housing cover into contact with the sealing material on the revolving frame to cause damages to the sealing material.